Firearm accessory



Dec. 5, 1944. W L, SWARTZ 2,364,487

FIREARM ACCESSORY Filed Aug. 22, 1942 @y QZ;

Patented Dec. 5, 1944 2,364,481 l FIREARM ACCESSORY William L. Swartz,West Hartford, Conn., assigner to Colts Patent Fire Arms ManufacturingCompany, Hartford, necticut Conn., a corporation of Con- ApplicationAugust 22, 1942, Serial No.,4'55,719

12 Claims.

, This invention relates to an accessory for holding a barrel extensionin its normal proper position within the breech casing of an automaticfirearm while the barrel or tube is being attached to or detached fromengagement with the barrel extension.

The invention is particularly applicable to firearms of the typebasically illustrated and de- "scribed in U. S. Patent 1,525,065 toBrowning dated February 3, 1925. The details of the portions of thefirearm immediately adjacent the barrel extension, such as the breechcasing and feed box, with which the present invention is directlyengageable, are shown to good advantage in the co-pending lapplicationof Frederick T. Moore, Serial No. 305,240, filed November 20, 1939. Fora description of details of the firearm which are not illustrated and/or described in the present drawing and specification, attention isdirected to said patentand co-pending application.

Automatic firearms of the type with which the present invention is to beused include a recuperator spring secured at one end to the lowerportion of the barrel extension to move the barrel and barrel extensionin counter-recoil direction following the recoil movement of the barreland barrel extension. The recuperator spring is necessarily very strongin order to quickly return the relatively heavy barrel to forwardposition following the recoil of the same. The strength of the spring issuch that the average person cannot manually move the barrel and barreleX- tension rearward against the force of the spring.

The barrel of such firearms is removable from the barrel extension andthe means for securing the barrel and barrel extension together comprisevery accurately-and precisely formed threads provided on the adjacentends of the barrel and barrel extension, the nature of the threads beingsuch that when these members are assembled in operative relationship,they function substantially the same as an integral unit and noperceptible play takes place between the barrel and barrel extension.The barrel is provided with an end having a diameter smaller than theouter diameter of the barrel, said end being threaded for coengagingwith a threaded aperture in the forward end of the barrel extension, thelength of the coengaging threaded portions being of the order of severalinches or more, whereby it will be apparent that the threaded apertureof the barrel extension must be accurately aligned with the threads ofthe barrel in order to permit the barrel to be .readily threaded intothe barrel exo5, Other objects and details tension. Even a relativelyslight misalignment of the barrel extension with respect to the barrelwill cause the threads to bind and possibly be injured if the threadsare forced while securing the barrel to' the barrel extension.

One end of the recuperator spring is secured to a depending memberintegral with the lower portion of the forward end of the barrelextension. The forward end of the barrel extension, when in forward orbattery position, abuts the rear face of the barrel bearing in thetrunnion block. The barrel extension is also provided with a pair ofspaced arms projecting rearwardly into the breech casing in a directionsubstantially parallel with the axis of the barrel. When the barrel isremoved from engagement with the barrel extension, it has been foundthat the force of the recuperator spring tends to urge the lower portionof the barrel extension forward, pivoting the lower portion of theforward end of the barrel extension against the rearward face of thebarrel bearing in the trunnion block, with the result that the rearwardends of the projecting arms of the barrel extension are moved downwardfrom their normal position and the axis of the threaded aperture in thebarrel extension is tilted from its normal position whereby when abarrel is threaded into the barrel extension while the barrel extensionis in said tilted position, binding between the threads of the barrelextension and barrel frequently takes place, and if turning of thebarrel with respect to the barrel extension is forced, damage to thethreads sometimes ensues.

It is therefore an object of the present invention to provide anaccessory adapted to engage one of the rearward projecting arms of thebarrel extension and maintain said ends against downward movement,whereby the threaded aperture of the barrel extension is maintained inproper alignment with respect to the breech casing and the axis of thebarrel bearing in the trunnion block, notwithstanding the tendency ofthe force of the recuperator spring to tilt the barrel extension out ofalignment.

It is another object of the invention to provide an accessory which willaccomplish the foregoing and be engageable with conventional andunmodified portions of the firearm whereby the accessory may be usedwith not only newly manufactured firearms but previously manufacturedfirearms without modification of the existing structure in the same. A

of the invention .are

elevation of an automatic firearm showing the.

barrel extension and the accessory comprising the present invention inoperative position with respect to the firearm.

Fig. 2 is a sectional end elevation of the firearm looking at the lefthand end of the fragment of the firearm illustrated in Fig. 1, portionsofl the rearm illustrated in Fig. l being omitted from Fig. 2.

Referring to the drawing, the rearm ED comprises a breech casing I2having opposed side plates I4 and I6, the forward portions of said sideplates being secured to a trunnion block I8 provided with a barrelbearing in which the rear portion of a barrel or tube 22 is slidablydisposed.

The rear portion of the barrel is provided lwith an end reduced indiameter from that of the exterior of the barrel, said reduced endhaving male threads 24 provided thereon for purposes to Vbe described.

The barrel extension 26 is adapted to be secured to the barrel and isdisposed within the breech casing for reciprocable movement in adirection longitudinally thereof. The forward portion or end 23 isprovided with a lower portion or member 3D depending from the undersidethereof. Said forward end is also provided with a cylindrical aperture32 provided with internal or female threads adapted to receive thethreads 24 of the barrel.

As stated above, the respective threads of the barrel and barrelextension are machined to a very high degree of precision and the tbetween the threadsis a very close one which permits no perceptible playbetween the barrel and barrel extension when connected, whereby when theadjacent ends of the barrel and barrel extension are in abuttingrelationship, the union between the barrel `and barrel extension issubstantially equivalent to that of two integral members. VIn order forthe barrel to be properly and readily threaded within the threadedaperture of the barrel extension, theaxis of the barrel and axis of theaperture of the barrel extension must be substantially perfectlyparallel.

A shaft 34 is secured tothe depending portion ofthe barrel extension bya nut 36 and a plunger or piston, not shown, is secured to the forwardend of said shaft and is adapted to abut againstthe forward end ofrecuperator spring 38, whereby the spring 38 may coact against saidplunger to move the barrel extension forward at the completion of therecoil movement of the` barrel extension.

The barrel extension 26 is also provided with a pair of spaced arms 4I!and 42 extending rearward into the breech casing, the arm 40 beingprovided with a cylindrical aperture 4d extending transverselytherethrough adjacent the rearward end of the same. Said aperture isnormally provided in the arm of the barrel extension for purposes ofengaging the barrel extension with a suitable supporting element duringthe heat treating of the barrel extension and is thus provided in thebarrel extension in the standard construction thereof.

A feed box 46 is attached to the upper portion of the breech casing andcomprises opposed side plates ri and 50 respectively secured to the sideplates `l4 and I6 of the breech casing by suitable screws or bolts 52.The side plate 48 Ais provided with an exit opening 54 for permittingthe exit of the empty feeder 56 therethrough. The side plate 50 isprovided with a relatively long opening or slot 58 on the entrance sideof the feed box for permitting the introduction of unfired cartridgesorrounds and feeder to the feed box. It will be seen from Fig. 1 thatthe entrance slot 58 is muchlonger than the exit opening 54 and, as willbe observed from the above mentioned gure, extends rearward past the endof the arms 40 and lll2 and substantially the full length of theentrance side of the'feed box.

The arms 40 and 42 are providedk Withwear plates 6I) adjacent therearward ends of the arms and the barrel extension 26 is provided withanother wear'plate 62 on the underside thereof just rearward of thedepending portion 30. The wear plates 60 are adapted for slidingengagement with the lower surfaces of the inturned anges 64 respectivelyprovided at the upper edges of the side plates I4 and I6 .of the breechcasing. The wear plate 62 is adapted for sliding engagement with theupper surface of inturned flanges 66, one of which is not shown in Fig.1, extending inward from the lower edges of the side plates I4 and I6.When the `barrel extension is in proper alignment withA the breechcasing, the wear plates 6G are in engagement with the flanges 64 and thewear plate 52 is in engagement with the flanges 66. The axis of theaperture 32 is also parallel to the axis of the barrel bearing 20 in thetrunnion block I8 when the barrel extension is in -proper alignment withthe breech casing and further, when the forward end of the barrelextension is in engagement with the rearward face of the barrel bearing20, and is otherwise in the position just described, said position isregarded as'the normal position and lis so considered hereinafter in theclaims.

When the barrel is removed from engagement with the barrel extension,the tension of the spring 38 is of such strength that it urges the loweror depending portion 30 of the barrel extension forward by pivoting thelower forward portion of the forward face of the barrel extension on thelower portion of the rear face of the trunnion block with the resultthat the rearward ends of the arms 4I) and 42 of the barrel extensionare moved downward a small fraction of an inch as indicated bythe dotand dash line position of the rearward ends of the arms in Fig. 1. Theposition of the arms in dot and dash lines in Fig, 1 is slightlyexaggerated to better lillustrate and indicate the lowermost position towhich the rearward ends of the arms are moved.

If the barrel is attempted to be threaded into the threaded aperture ofthe barrel extension while in such tilted or misaligned position,binding takesY place between the respective threads of the barrel andbarrel extension and threading of the barrel into the barrel extensionunder such conditions takes place only with great difficulty I if it isat all possible to completely thread the barrel into proper position.ATo force the threads under such conditions results in various degrees ofinjury to the threads and such practice greatly moving the cotter pin18. The accessory is thus reduces the eifective life of these respectiveparts of the rearm.

The `foregoing description deals with'only the elements and portions ofthe firearm necessary to afford an understanding of the operation ofthose parts of the firearm which are engaged by the accessory comprisingthe present invention. For a more complete understanding of the parts ofthe rearm illustrated on the drawing but not described in detail in theforegoing, attention is directed to the above mentioned Patent 1,525,065to Browning in which a full and complete description of the operation ofthe entire firearm is set forth.

The present invention comprises an accessory adapted to engage therearward portion of one of Y the arms of the barrel extension to holdthe same in normal or uppermost position, against the action or force ofthe spring 38, whereby the axis of the threaded aperture of the barrelextension will be maintained in proper position and substantiallyparallel to the axis of the barrel bearing.

The accessory includes a bar forming a bridging member 68 havingangularly related end portions, the angle between the two portions beingsubstantially a right angle although the shape of the bridging member isnot to be restricted to a right angle. One portion of the bridgingmember is provided with an aperture '18, said portion being adapted tobe disposed on the upper edge of the side plate 48 of the feed box forsupport thereby. The other angularly related portion of the bridgingmember is adapted to abut the upper side of the flange 64 of the sideplate I6 of the A portion of the connecting member l2 to form a barrelengaging member or portion 80 which might be defined as a hook-likemember adapted to be disposed in the aperture 44 normally providedadjacent the rearward end of one of the arms 40 of the barrel extension.

The connecting member 12 is freely movable with respect to the bridgingmember '68, whereby after the portion 80 has been disposed in theaperture 44 and theend portions of the bridging member 68 arerespectively placed in engagement with the upper edge of one side of thebreech casing and one side of the feed box for support thereby, the wingnut 16 may be rotated to raise the rearward end of the arm 40 of thebarrel fextension and move the upper surfaces of the rearward ends ofboth of the arms of the barrel extension into engagement with the lowersurfaces of the anges 64 and thus maintain the barrel extension in saidposition which is the 4normal position thereof. The effect of the forceof the spring 38 tending to tilt the barrel extension out of normalposition is thereby overcome and the threaded aperture of the barrelextension is in proper position to receive the threads of the barrel andhave the same' freely engage the threads of the barrel extension.

It will also be seen that the arrangement of the various parts of theaccessory is such that said parts may not be disassembled withoutremaintained in assembled relationship and free from accidentalseparation of the various parts thereof.

After the barrel has been threaded into proper engagement with thebarrel extension, the ac cessory may be quickly removed by loosening thewing nut 'I6 and removing the portion 80 from the aperture 44, followingwhich the accessory may be vertically removed from the interior of thebreech casing and feed box.

The bridging member B8 is formed with angularly related portions, one ofwhich portions extends downward to engage the upper portion of the edgeof the side plate t6 of the breech casing in order to afford a rigidbase for supporting said portion of the bridging member. Were the brideEing. member extended horizontally across both upper edges of theopposite sides of the feed box, in view of the slot 58 extendingsubstantially the full length of the side 58 of the feed box, rm

support for the left hand end of the bridging member, as viewed in Fig.2, would not be afforded. In order that firm support for both ends ofthe bridging member may be provided, it is formed as described andillustrated.

The term casing as used in the claims is not to be restricted to eitherthe feed box or the breech casing. but may be considered in the broadersense of an enclosure comprising both the feed box and breech casing.

The descriptive terms of position such as upward, downward forward,rearward and the like are relative terms to be considered with respectto the position of the rearm shown in Figs. l and 2 and in which thenormal position of the firearm is considered to be that in which thefeed box is disposed above the breech casing and the barrel end of thefirearm is considered the forward end. The position of the variouselements and parts of the firearm and accessory are to be considered inthis same relative sense regardless of the position in which the gun maybe otherwise disposed.

It will thus be seen that the present invention provides a simplyconstructed accessory forming a durable and eicient supporting orclamping means for securing the barrel extension in its normal positionwithin the breech casing and prevents displacement or movement of thebarrel extension from said normal position in order to maintain thebarrel extension inproper alignment to freely receive the threaded endof the barrel, notwithstanding the force of the recuperator springtending to disalign the barrel extension and move it from its normalposition. The accessory is quickly attached to and removed from thefirearm and the various parts of the accessory are so assembled thatthey will not become readily separated from each other.

While the invention has been illustrated and described in its preferredembodiment and has included certain details, itshould be understood thatthe invention is not to be limited to the precise details hereinillustrated and described since the same may be carried out in otherways, fal1 ing within the scope of the invention as claimed.

What I claim is:

l. An accessory for use with a firearm having a barrel removably securedto a barrel extension reciprocably mounted in a casing and a recuperatorspring secured to said barrel extension in such a manner that it tendsto move the barrel extension out of proper alignment with the casingwhen the barrel is removed, said accessory comprising supporting meansadapted to engage said casing for support thereby and means adapted toconnect said barrel extension and supporting means to secure said barrelextension in proper alignment with said casing and immovable against theforce of said recuperator spring tending to disalign said barrelextension with respect to'said casing while the barrel is being securedto or removed from said barrel extension.

2; An accesso-ry for use with a i-lrearm having a barrel removablysecured to one end of a barrel extension reciprocably mounted in acasing and a recuperator spring secured to said end of said barrelextension in such a manner that it tends to move the barrel extensionout of proper alignment with the casing when the barrel is removed, saidaccessory comprising supporting means adapted to engage the casing forsupport thereby and means adapted to connect said supporting means andbarrel extension adjacent the other end thereof to secure said barrelextension in proper axial alignment with said casing and im-.

' said barrel extension as said barrel and adjacent one side of said endwhereby the spring tends to move the other end of the barrel extensionfrom its normal position in the casing when the barrel is removed fromthe barrel extension, said accesso-ry comprising in combination, abridging member adapted to engage and be disposed across said casing,and connecting means engaging said bridging member and adapted to engagesaid other end of the barrel extension and secure said other end of thebarrel extension against movement in a direction transverse to thelongitudinal axis of the 'firearm while the barrel is being secured toor removed from ysaid barrel extension.

4. An accessory for use with a rearm having a barrel removably securedto one end of a barrel extension reciprocably mounted in a casing and arecuperator spring secured to the same end of said barrel extension assaid barrel .and adjacent one side oi said end whereby the spring tendsto move the other end of the barrel eX- tension from its normal positionin the casing when the barrel is removed from the barrel extension, saidaccessory comprising in combination, a bridging member adapted to extendacross said casing and having portions respectively adapted to engagetheedges kof opposed walls of said casing, and connecting means engagingsaid bridging member and adapted to engage said other end of the barrelextension and secure said other end of the barrel extension againstmovement in a direction transverse to the longitudinal axis of thefirearm while the barrel is being secured to or remo-ved from saidbarrel extension.

5. An accessory for use with a firearm having a barrel removably securedto one end of a barrel extension provided with an aperture adjacent itsother end and reciprocably mounted in a casing and the rearm also havinga recuperator spring secured to the same end of said barrel extension-as said barrel and adjacent one side of said end whereby the springtends to move the other end of the barrel extension from its normalposition in the casing when the barrel is removed from the barrelextension, said accessory comprising in combination, a bridging memberadapted to extend across Vthe casing and having portions adapted torespectively engage the edges of opposed walls of said casing, andconnecting means having one end kengaging said bridging member and theother end adapted to engage the aperture in said other end of the barrelextension to secure the other end of said barrel extension againstmovement in a direction transverse to the 1ongi` tudinal axis of thefirearm while the barrel is being secured to or removed from said barrelextension.

6. An accessory for use with a firearm having a barrel removably securedto one end of a barrel extension reciprocably mounted in a casing and arecuperator spring secured to the same end of said barrel extension assaid barrel and adjacent one side of said end whereby the spring tendsto move the other end of the barrel extension from its normal positionin the casing when the barrel is removed from the barrel extension, saidaccessory comprising in combination, bridging means r aadpted to extendacross said casing `and having portions respectively adapted to engageedges'oi opposed walls of said casing, and connecting means comprising amember movable with respect to and having one end engaging said bridgingmember and the otherend adapted to engage the barrel extension adjacentsaid other end thereof to secured said other end of the barrel extensionin its normal position in said casing and against movement in adirection transverse to the longitudinal axis of the rearm while thebarrel is being secured to or removed from said barrel extension.

'7. An accessory for use with a rearm having a barrel removably securedto one end of a barrel extension reciprocably mounted in a casing and arecuperator spring secured to the same end of said barrel extension assaid barrel and adjacent one side of said end whereby the spring tendsto move the other end of the barrel extension from its normal positionin the casing when the barrel is removed from the barrel extension, saidaccessory comprisingin combination, an apertured bridging member adaptedto extend across said casing and having portions respectively adapted tcengage edges of opposed walls of said casing, connecting means movablewith respect to said bridging member and having one end passing throughthe aperture of saidY bridging member and the other end adapted toengage the barrel extension adjacent said other end thereof, and meanson said connecting means adapted to engage said bridging member-tomaintain said connecting means and said other end of the barrelextension against movement in a direction transverse to the longitudinalaxis of the firearm while the barrel is being secured to or removed fromsaid barrel extension. A

8. An accessory for use with a firearm having a barrel removably securedto one end of a barrel extension reciprocably mounted in a casing and arecuperator spring secured to the lower portion of the same end of saidbarrel extension as said barrel whereby the spring tends to move theother end of the barrel extension downwardfrom its normal position inthe casing when the barrel is removed from the barrel extension, said accessory comprising in combination, a bridging member adapted to extendacross said casing and having portions respectively adapted to engagethe upper edges of opposed Walls of said casing,

and a connecting member engaging said bridging member and adapted toengage said other end of the barrel extension to maintain it againstdownward movement transverse vto the longitudinal axis of the rearmwhile the barrel is being secured to or removed from said barrelextension.

9. An accessory for use with a firearm having a barrel removably securedto one end of a barrel extension reciprocably mounted in a breech casingprovided with a feed box and the iirearm also having a recuperatorspring secured to the same end of said barrel extension as said barreland adjacent the lower side of said end whereby the spring tends to movethe other end of the barrel extension in a direction downward andtransverse to the longitudinal axis of the rearm when the barrel isremoved Yfrom nthe barrel extension, said accessory comprising incombination, an irregularly shaped apertured bridging member adapted toextend across said casing and having portions respectively adapted toengage one wall of said breech casing and an opposed wall of said feedbox, connecting means movable with respect to said bridging member andhaving one end passing through the aperture of said bridging member andthe other end adapted to engage said barrel extension adjacent saidother end thereof, and means on said connecting member adapted to engagesaid bridging member to maintain the connecting member and said otherend of the barrel extension against movement in a direction transverseto the longitudinal axis of the firearm to engage said breech casing andbe supported thereby, said bar having an aperture intermediate its ends,a rod disposed in said aperture, said rod being threaded on one end andprovided on its other end with means arranged to engage said barrelextension, and threaded means on the threaded end of the rod adapted tomaintain the rod in an adjustable position on said bar.

11. Clamping means for engaging one end of a firearm barrel extensionand holding it in proper position in a firearm breech casing, saidclamping means comprising in combination, a bar having angularly relatedportions arranged to engage said breech casing and be supported thereby,said bar also having an aperture intermediate itslends, a rod disposedin said aperture, said rod being threaded on one end and provided on itsother end with a hook-like portion adapted to engage the barrelextension, and means on the threaded end of the rod adapted to maintainthe rod in an adjustable position on said bar.

l2. Clamping means for engaging one end of a firearm barrel extensionand holding it in proper position in a firearm breech casing, saidclamping means comprising in combination, a bar having angularly relatedportions arranged to engage said breech casing and be supported thereby,said bar also having an aperture intermediate its ends, a rod disposedin said aperture, said rod being threaded on one end and provided `onits other end with a portion extending transversely thereto and adaptedto engage the barrel extension, a

nut disposed on the threaded end of said rod and i adapted to maintainthe rod in an adjustable position on said bar, and locking means on theouter portion of the threaded end of the rod to prevent removal of thenut from the threaded rod and maintain the clamping means assembled.

A WILLIAM L. SWARTZ.

